The big obesity debate

Academics and health experts are divided on the effects
of junk-food advertising.

Ban all ads for junk food. Stop TV personalities doing
commercials for sugar-laden breakfast cereals and banish
pester-power promotions for fast food from the airwaves. Then the
quarter of Australian children who are overweight, including the
one in 20 who are obese, would trim their overfed tummies, wouldn't
they?

Perhaps not. Such a social revolution is doubtful - and not
merely because the Federal Government has made it clear a ban is
out of the question, preferring advertisers and TV stations to
regulate themselves on junk-food advertising matters.

It's in doubt because, according to public health researcher
Owen Carter, the link between television watching and childhood
obesity is "surprisingly weak". Based on a review of studies that
compared how many hours of television children watched a day with
how fat they were, he says, a child's TV viewing can only affect
about 1 per cent of body weight.

Carter, who recently published a review of literature on the
link between childhood obesity and food advertising on Australian
television in the Health Promotion Journal of Australia,
found no direct evidence to link junk-food advertising with
childhood obesity.

He argues that, by deduction, any contribution of junk-food ads
"has to be less than the 1 per cent total" in the difference TV
watching makes to children's weight. "That is, half of bugger all,"
he says.

Further, Carter found a lack of exercise was not the great
problem among those who watch TV. Children who watch less than the
average of two hours a day simply replace TV with other sedentary
activities such as reading and listening to music.

Overall, Carter makes the heretical finding that there is little
evidence children today are more sedentary than their parents or
grandparents.

Carter does not quibble with the fact childhood obesity rates
have tripled over the past 20 years. But he blames parents for
feeding their children too much junk.

Parents who regularly consume junk food and soft drinks are much
more likely to let their children do the same, Carter says. "This
is why a child with obese parents is 10 times more likely to be
obese [than children without obese parents]."

Carter, a research fellow at the Centre for Behavioural Research
in Cancer Control at Perth's Curtin University of Technology, has a
big interest in fighting obesity, as it is related to increased
deaths from various forms of cancer. His $120,000 funding for the
study comes from the Australian Research Council.

"I fully expected there to be plentiful and sound evidence of a
significant relationship between junk-food advertising and
childhood obesity," he says. "However, the deeper I delved, the
more confused I became, because I couldn't actually find any
evidence at all.

"The only data I found contradicted this position entirely,
until I was begrudgingly forced to accept that there actually was
no evidence of a relationship at all."

From Sunday, the world's health experts will gather in Sydney
for the 10th International Congress on Obesity. High on the agenda
is a debate about whether childhood obesity can be reduced "without
the heavy hand of government", such as putting the brakes on
advertisers.

VicHealth chief executive Rob Moodie will be arguing the case
for government intervention. He dismisses Carter's paper as "more
narrative than systematic review" and says its findings contradict
systematic US and British reviews.

Moodie says it is very difficult to conduct studies that would
give you a statistic on how much an impact food advertising has on
weight because there are so many other factors that can't be
measured.

Children today are more sedentary than their parents or
grandparents, he argues, and are heavily influenced by junk-food
advertising. Since the mid-1970s, Moodie says, Australia has
suffered a "market-driven obesity epidemic", in which food
manufacturers worked out how to "ram a lot of calories down your
throat" at the same time as backyards started getting smaller and
children started playing less often in the street and thus getting
less exercise.

OVERSEAS RESEARCHERS CHEW THE FACTS

The US Institute of Medicine's Food Marketing to Children and
Youth report released last December found "strong evidence"
television advertising influences the food and beverage preferences
and requests of children aged two to 11. However, there was
insufficient evidence of its impact on the preferences and requests
of children aged 12 to 18.

There is "strong evidence" TV advertising is associated with
adiposity or fat in children, the US researchers found - although
on current evidence, the Institute of Medicine says, it cannot be
said TV ads cause children to get fat.

A systematic review conducted on behalf of Britain's Food
Standards Agency in 2003 found a "probable" link between the
content and number of junk food advertisements and children's
weight gain.

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